The present invention relates to a mixing system for allowing an audio mixer to remote-control external or peripheral devices that are involved in audio signal processing.
Among the conventionally-known digital audio mixers are ones to which can be connected an external device or peripheral device corresponding to remote operation based on a dedicated communication protocol. For example, a digital audio mixer marketed by the assignee of the instant application under the trade name “PM5D” and a head amplifier marketed by the assignee of the instant application under the trade name “AD8HR” are provided with respective dedicated remote terminals (such as serial communication interfaces of the RS422 standard), and the head amplifier can be controlled by the mixer by connecting the mixer and head amplifier using a physical cable (functioning as a control line) compliant with the communication standard of the remote terminals. Further, the head amplifier is connected to the mixer via a physical cable (functioning as an audio line) compliant with a predetermined digital audio signal transmission standard, such as the AES/EBU standard, and audio signals of a plurality of channels input from an input device, such as a microphone, into the head amplifier are output to the digital audio mixer over the audio lines. Namely, two different types of cables, i.e. one physical cable functioning as an audio line for transmitting audio signals and another physical cable functioning as a control line for transmitting control signals for the remote control, are installed to extend between the head amplifier and the mixer.
A plurality of head amplifiers can be connected, in a “daisy-chain connection” configuration, to the conventionally-known digital mixer. The head amplifiers each include two remote terminals, so that these head amplifiers can be interconnected, e.g. by connecting one remote terminal of the first head amplifier to the remote terminal of the mixer, connecting one remote terminal of the second head amplifier to the other remote terminal of the first head amplifier, connecting one remote terminal of the third head amplifier to the other remote terminal of the second head amplifier, and so on. The individual head amplifiers connected to the mixer are automatically assigned serial ID numbers with the leading ID number being assigned to the first head amplifier connected directly to the remote terminal of the mixer (see, for example, http://www2.yamaha.co.jp/manual/pdf/pa/japan/mixers/PM5DJI.pdf, and http://www2.yamaha.co.jp/manual/pdf/pa/japan/others/ad8 hr_ja_om.pdf).
FIG. 7 is a block diagram showing an example construction or setup of a conventional mixing system where a plurality of head amplifiers are “daisy-chain” connected to a mixer. Here, one mixer 1 and the plurality of (12 (twelve) in the illustrated example of FIG. 7) head amplifiers 2 are connected, in a daisy-chain configuration, via a control-signal transmitting control line 3. The individual head amplifiers 2 are automatically assigned serial ID numbers “#1”, “#2”, “#3”, . . . , “#12” with the leading ID number being assigned to the head amplifier connected directly to the remote terminal of the mixer 1. Once the mixer 1 transmits, over the control-signal transmitting control line 3, control signals containing the ID number of a particular one of the head amplifiers 2, which is to be remote-controlled, the control signals are transferred between the head amplifiers 2 in the order the head amplifiers 2 are daisy-connected. Then, only the particular head amplifier 2 receives the control signals, so that settings of various parameters of the particular head amplifier 2 can be remote-controlled per channel by the mixer 1. As illustrated in FIG. 7, digital audio signals are transmitted from the individual head amplifiers 2 to the mixer 1 over audio lines 4, and one such audio line 4 for transmitting audio signals is installed per head amplifier 2; thus, 12 (twelve) audio lines 4 extending from the 12 head amplifiers 2 are connected to the mixer 1. Note that, in FIG. 7, the control line 3 is indicated by a thick line while the audio lines 4 are indicated by thin lines.
Generally, in a large-size concert venue, for example, the mixer 1 is installed within a control booth located in a central area, rear end area or the like of the concert venue, while the head amplifiers 2 are installed near input equipment on the stage (e.g., on a side of the stage). The reason why the head amplifiers 2 are installed near the input equipment is that it is desirable that analog audio lines connecting the head amplifiers 2 and the input equipment be as short as possible with a view to preventing unwanted mixing-in of noise, degradation of tone quality, etc.
However, because the installed positions of the mixer 1 and the head amplifiers 2 are physically distant from each other, the control line 3 and audio lines 4 extending between the mixer 1 and the head amplifiers 2 would have very great lengths. In addition, because one audio line 4 extends from each of the head amplifiers 2, the total number of the audio lines 4 would increase as the number of the head amplifiers 2 to be installed increases; thus, a multiplicity of the audio lines 4 have to be provided depending on the number of the head amplifiers 2 to be installed. Thus, with the conventional mixing system, operation for installing wiring between the mixer 1 and the head amplifiers 2 tends to be very cumbersome and require high wiring cost.